Question: $(-90-27i)-(66+34i)=$ Express your answer in the form $(a+bi)$.
Answer: Background Complex numbers can be added or subtracted by separately adding or subtracting their real and imaginary terms. To add or subtract complex numbers: Expand parentheses (attending to minus signs outside of parentheses if necessary) Combine all real terms (terms that do not contain $i$ ), and add or subtract them. Combine all imaginary terms (terms that contain $i$ ), and add or subtract them. Combining Like Terms $\begin{aligned} ({-90}{-27}i)-({66}+{34}i)&={-90}{-27}i-{66}-{34}i \\\\ &={-90}-{66}{-27}i-{34}i \\\\ &={-156}{-61}i \end{aligned}$ Summary $({-90}{-27}i)-({66}+{34}i)={-156}{-61}i$